1. Field of the Invention
The present invention relates to a human cooperation robot system in which a robot is caused to perform a retreat operation depending on an external force acting on the robot.
2. Description of the Related Art
In recent years, a human cooperation robot system has been developed in which a human and a robot are deployed in a mixed manner on a production site and a production operation is divided between the human and the robot. In some cases, a safety fence is provided between a human and a robot in order to secure the human's safety. However, providing a safety fence could lead to a delay in the operation; therefore, there has recently been proposed a human cooperation robot system in which a safety fence is not used.
In such a human cooperation robot system, when the robot approaches or contacts the human, the robot is decelerated or stopped in order to ensure the human's safety. However, since the human and the robot share the same operation area, a case may occur in which the decelerated or stopped robot constitutes an obstacle when the human carries out an operation.
Thus, it is preferable that the robot be made to retreat from the operation area in such a situation. To this end, the robot is provided with a sensor that detects an external force imparted to the robot when the human pushes against the robot. As a result, the robot is caused to perform a retreat operation simply by the human pushing against it with an external force greater than or equal to a predetermined value. In this case, it is not necessary to use a teaching operation panel.
In Japanese Patent No. 4,445,038 Publication, in a system in which a human and a robot convey a workpiece in cooperation with each other, there is provided a sensor that detects an external force acting between the workpiece and a hand of the robot. In Japanese Patent Laid-open Publication No. H10-291182, a configuration is disclosed in which a torque sensor is provided between a motor and an arm driven by the motor.